1. Field of the Invention
This invention relates to a product usable for making industrial components such as friction linings for clutches or brakes.
2. Description of the Prior Art
Inorganic, e.g. metallic friction products are already known which, when fixed in the form of linings to supports, constitute so-called friction linings.
In metal-base friction linings, the substances controlling the friction and/or slip properties and the physical properties thereof are embedded in a sintered metal bond. Therefore, these linings are generally manufactured by applying the techniques of powder metallurgy from a mixture of metal and non-metallic powders which is applied to a support before sintering same in a suitable oven or under pressure.
The most common linings nowadays consist of a mixture having a high content of asbestos fibres, elastomer or metal chips, with a possible addition of substances capable of imparting specific properties to the lining. These additional substances may be for instance carbon for preventing variations in the coefficient of friction; alumina or silica for preventing the transfer of material from the rotating part to the lining; certain high-temperature inorganic salts permitting the stabilisation of the coefficient of friction at high temperatures. The cohesion of the lining compound is obtained by using a suitable thermostable resinoid binder. High-temperature linings used notably in aircraft comprise a copper or iron metal base and some of the additional elements mentioned hereinabove. Sometimes other additives are also incorporated in the lining compound in order to promote the sintering thereof and improve its high-temperature resistance.
Asbestos-free semi-metallic linings now marked out for a considerable growth are obtained from comminuted metal with the addition of the above-mentioned substances. In this case, the lining cohesion is obtained by using a thermostable resinoid binder.
The metal particles used for making these last two types of linings are obtained when the basic metal is iron by applying either a powder metallurgy process or a fibrous-product making process.